Home | History | Annotate | Download | only in sys 
      1 /* ----------------------------------------------------------------------- *
      2  *
      3  *   Copyright 2003-2008 H. Peter Anvin - All Rights Reserved
      4  *
      5  *   Permission is hereby granted, free of charge, to any person
      6  *   obtaining a copy of this software and associated documentation
      7  *   files (the "Software"), to deal in the Software without
      8  *   restriction, including without limitation the rights to use,
      9  *   copy, modify, merge, publish, distribute, sublicense, and/or
     10  *   sell copies of the Software, and to permit persons to whom
     11  *   the Software is furnished to do so, subject to the following
     12  *   conditions:
     13  *
     14  *   The above copyright notice and this permission notice shall
     15  *   be included in all copies or substantial portions of the Software.
     16  *
     17  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     18  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
     19  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     20  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
     21  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
     22  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     23  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     24  *   OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  * ----------------------------------------------------------------------- */
     27 
     28 #include <errno.h>
     29 #include <com32.h>
     30 #include <string.h>
     31 #include <unistd.h>
     32 #include "file.h"
     33 
     34 /*
     35  * opendev.c
     36  *
     37  * Open a special device
     38  */
     39 
     40 int opendev(const struct input_dev *idev,
     41 	    const struct output_dev *odev, int flags)
     42 {
     43     int fd;
     44     struct file_info *fp;
     45     int okflags;
     46     int e;
     47 
     48     okflags = (idev ? idev->fileflags : 0) | (odev ? odev->fileflags : 0);
     49 
     50     if (!(flags & 3) || (flags & ~okflags)) {
     51 	errno = EINVAL;
     52 	return -1;
     53     }
     54 
     55     for (fd = 0, fp = __file_info; fd < NFILES; fd++, fp++)
     56 	if (!fp->iop && !fp->oop)
     57 	    break;
     58 
     59     if (fd >= NFILES) {
     60 	errno = EMFILE;
     61 	return -1;
     62     }
     63 
     64     /* The file structure is already zeroed */
     65     fp->iop = &dev_error_r;
     66     fp->oop = &dev_error_w;
     67     fp->i.datap = fp->i.buf;
     68 
     69     if (idev) {
     70 	if (idev->open && (e = idev->open(fp))) {
     71 	    errno = e;
     72 	    goto puke;
     73 	}
     74 	fp->iop = idev;
     75     }
     76 
     77     while (odev) {
     78 	if (odev->open && (e = odev->open(fp))) {
     79 	    if (e == EAGAIN) {
     80 		if (odev->fallback) {
     81 		    odev = odev->fallback;
     82 		    continue;
     83 		} else {
     84 		    e = EIO;
     85 		}
     86 	    }
     87 	    errno = e;
     88 	    goto puke;
     89 	}
     90 	fp->oop = odev;
     91 	break;
     92     }
     93 
     94     return fd;
     95 
     96 puke:
     97     close(fd);
     98     return -1;
     99 }
    100